This invention relates to a fulgimide derivative having photochromic activity and useful as recording and memory materials, copying materials, printed photosensitive bodies, photosensitive materials for laser, photosensitive materials for photo-composing, photosensitive materials for display, etc.
Compounds having properties of producing changes in absorption spectra when exposed to irradiation of ultraviolet light, or visible light of short wavelength, are generally called photochromic compounds. These photochromic compounds are expected to be useful as recording and memory materials, copying materials, printed photosensitive bodies, photosensitive materials for laser, photosensitive materials for photo-composing, photosensitive materials for display, etc. As these photochromic compounds, there are generally well known azobenzenes, viologens, triphenylmethanes, spirobenzopyrans, spironaphthoxazines, fulgides, etc. Among these compounds, spirobenzopyrans and spironaphthoxazines are widely studied now. These compounds form colors when exposed to light, but have a defect in that fading takes place by heat even if stored in the dark. Therefore, these are problems in using these compounds as recording media.
On the other hand, fulgide compounds form a color by exposing such to light of 300 to 400 nm, and the color formed hardly fades by heat but extinguish the color by visible light. Thus, the fulgide compounds have recently been noticed as a photochromic compound useful as a recording medium. The fulgide compounds include fulgide derivatives having a structure of dicarboxylic anhydride and fulgimide derivatives. Among them, the fulgide derivatives have problems in water resistance and heat resistance due to having the structure of dicarboxylic anhydride. Therefore, the fulgimide derivatives are noticed as a recording medium.
The fulgimide derivatives are produced, for example, as follows:
A compound of the formula: ##STR2## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently a hydrogen atom, a halogen atom, an alkyl group which can have one or more substituents, an alkoxy group, a cycloalkyl group, an aryl group, an aralkyl group or an aryloxy group, or R.sup.2 and R.sup.3 may be bonded each other to form a ring group such as an adamantyl group, a norbornyl group, etc.; R.sup.4 is a group of the formula: ##STR3## wherein R.sup.1 ' is a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group; R.sup.2 ', R.sup.3 ', R.sup.4 ' and R.sup.5 ' are independently a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, an aryloxy group or a halogen atom; W' is an oxygen atom, a sulfur atom, a selenium atom or =N-R.sup.6 '; R.sup.6 ' is a hydrogen atom, an alkyl group, an aralkyl group or an aryl group; R" is an alkyl group, is reacted with EQU R.sup.# NHMgBr
wherein R.sup.# is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group, to form a corresponding succinimide acid, followed by reaction with an acid chloride or acid anhydride to yield a fulgimide derivative of the formula: ##STR4## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.# are as defined above (German Offenlegungsschrift 2,441,759 and 2,647,850).
Alternatively, a compound of the formula: ##STR5## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as defined above is reacted with EQU R.sup.# NH.sub.2
wherein R.sup.# is as defined above, to form a succinimide acid, followed by reaction with an acid chloride or an acid anhydride to yield a fulgimide derivative of the formula [I'] (German Offenlegungsschrift 2,441,759 and 2,647,850).
According to these processes, since an acid chloride or acid anhydride is used in the reaction, it is very difficult to synthesize fulgimide derivatives having a reactive functional group such as an amino group, a hydroxyl group, or the like. Further, it is more difficult to introduce a functional group such as an amino group, a hydroxyl group, or the like into the fulgimide derivative of the formula [I'] thus synthesized.
The fulgimide derivative of the formula [I'] has no reactive functional group, so that its application is limited to i) mixing with a suitable monomer for polymerization and molding, ii) dissolving with a suitable solvent to dye a molded resin therein, and iii) dissolving with a suitable solvent for use as a coating composition, an ink, a dye, etc. Further, articles obtained by coating with a fulgimide derivative of the formula [I'] or mixing a polymer with a fulgimide derivative of the formula [I'], followed by molding, are not only poor in water resistance (release of the fulgimide derivative by washing with water) and chemical resistance, but non-uniform in color formation when exposed to light. Improvement of these defects has long been desired.